1. Field of the Invention
The invention relates to a stand for receiving machines and equipment, including horizontally and vertically extending beams constructed as hollow profile sections, and junction nodes being disposed in a plurality of planes and with which the beams enter into a form-locking connection. A form-locking connection is one which connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by force external to the elements.
One such stand is known from German Utility Model DE 92 12 546 U1. In that device, in order to produce the form-locking connection, the lateral surfaces of the cube-shaped junction node have protuberances adapted to the cross section of the inner peripheral surface of the beam. Each lateral surface of the junction node is also provided with apertures, which are constructed as a polygon or a T-groove, for receiving a connecting strap, which is fixed relative to the junction node by a transverse pin. The connecting strap protrudes with its free end into the interior of the beam and is fixed with a clamping screw that passes through the connecting strap and the beam wall.
Multiple-part clamping, elements are associated with the clamping screw and by radial displacement they are intended to effect a fixation of the beam relative to the junction node. Despite the major effort and expense of producing the junction node and the complicated construction of the clamping elements coupled to the clamping screw, the clamped junction node cannot be prevented from becoming loose, in the event that the stand is jarred or shaken.
In a structural part for frames and/or load-bearing constructions which is known from German Utility Model DE 88 11 309 U1, recesses of a cube-shaped node body are engaged by a connecting profile piece, which has an end remote from the node body that engages a beam constructed as a hollow profile. The connecting profile piece is screwed through a central bore to the node body, while a connecting screw oriented transversely to the axis is provided between the connecting profile piece and the beam. The mode of connection lacks effective bracing between the node body and the beam, and so that an unstable connection cannot be precluded.
A machine frame is also known from German Patent DE 849 499, in which hollow sheet-metal spacers are disposed between its stanchion elements. The spacers and the stanchions are penetrated by tie bolts. Neither a junction node nor a form-locking connection is provided.